It is known to attach panels to substrates on a vehicle with adhesives, particularly glass panels for windows, sunroofs or transparent roofs, decorative panels, and the like. The substrate may be a separate frame holding the panel, which is mounted on a vehicle body or the substrate may be a frame or part integrally formed with a vehicle body.
One known procedure for mounting the panel uses two separate adhesives: a primary adhesive providing long term adhesion and a fast curing, secondary adhesive that provides stability to the panel as the primary adhesive cures. Once the vehicle is fully assembled, the secondary adhesive remains between the installed panel and substrate on the vehicle and can provide stability not only during the entire curing process of the primary adhesive, but also during manufacturing.
Since the secondary adhesive is often made of a relatively stiffer material compared to that of the primary adhesive, the secondary adhesive absorbs concentrated loads from the substrate during motion of the vehicle. This has a tendency to cause a failure, in which case, the secondary adhesive can delaminate from either the substrate or the glass panel. In this case, once the secondary adhesive is delaminated from one of the bonded surfaces, further motion between the secondary adhesive and the substrate can cause the secondary adhesive to impact with the opposing surface. This can result in an objectionable, annoying sound such as squeaking or ticking that is audible from the passenger compartment or extension of the vehicle.